In modern aeroplane construction, alongside classic metallic materials such as, for example, aluminium alloys and titanium alloys, components made from plastic materials increasingly also find application in the structural field. By this means a high potential for weight saving ensues, which amongst other factors leads to a reduced fuel consumption in flight operations. Moreover, in comparison to metallic materials, plastic materials have a higher corrosion resistance, as a result of which in particular the maintenance effort can be significantly reduced. Carbon fibre- or glass fibre-reinforced thermoplastic high-performance plastics, or fibre-reinforced thermosetting plastics, are widely deployed as the plastic materials. The joining together of metallic materials and plastic materials in many cases takes place by means of connecting elements, such as for example, rivets or bolts. However, additional weight is introduced into the structure by these connecting elements. In addition, the necessary holes in the components represent a structural weakening of the overall structure, and moreover require a high level of production effort. Thermal joints for such components feature in contrast a high load-bearing capability and require no additional connecting elements. Frequently, however, the thermal joining together of thermoplastic plastic components with one another, or of plastic components with metallic components causes significant technical process problems, since, amongst other factors, ensuring that the effects of the necessary joining temperatures are locally limited represents a high level of procedural effort, and moreover the joining of large-scale thermoplastic components requires large furnaces. In addition, it is difficult to ensure a sufficiently high process reliability that will lead to reliably reproducible results for the joints.
US 2005/0082344 A1 describes a method for the thermal joining of metallic components with the use of flammable foils that are already sold under the trade name NANOFOIL. These foils are metallic reactive sheet entities constructed with an alternating sequence of thousands of layers of aluminium and nickel foils of minimal material thickness—in each case between 5 and 8 nm—is placed between the components to be joined and allows an exact local generation of the process heat that is necessary for the joining process. The central property of these reactive sheet entities consists in the fact that they can ignite as a result of a one-time supply of a small amount of energy, and thereby develop a temperature of between 1000° C. and 1500° C. in the region of the ignition front. After the reactive sheet entity has been ignited the temperature front automatically progresses through the reactive sheet entity with a speed of up to 50 m/s, so that the joining process is quickly completed. The thermal joining takes place preferably in the course of a soldering or brazing process as a consequence of the release of temperature by the reactive sheet entity. By virtue of the locally limited release of temperature any overheating of the components to be joined is all but ruled out. The reactive sheet entity can be provided on one or both sides with joint filler materials, for example, in the form of foils, in order to support the soldering processes. On account of the extraordinarily intense development of the temperature of the reactive sheet entities deployed, the thermal joining of components constituted from thermoplastic materials with a metallic component, or the welding of two components constituted from a thermoplastic material, is in particular impossible, since in the region of the reactive sheet entities temperatures are reached, which, as a rule, lie above the decomposition temperature of the thermoplastic plastics deployed.